490A - Team Olympiad - CodeForces Solution

if __name__ == '__main__':
    n = int(input())
    x = input().split()
    li = [int(i) for i in x]
    m1 = 0
    m2 = 0
    m3 = 0

    for i in li:
        if i == 1:
            m1 += 1
        elif i == 2:
            m2 += 1
        else:
            m3 += 1
    count = min(m1, m2, m3)

    if count == 0:
        print(0)
    else:
        l1 = []
        l2 = []
        l3 = []
        for i in range(0, len(li)):
            if li[i] == 1:
                l1.append(i + 1)
            elif li[i] == 2:
                l2.append(i + 1)
            else:
                l3.append(i + 1)

        print(count)
        for i in range(0, count):
            print(l1[i], l2[i], l3[i])